One similarity and one difference between an echo and a reverberation?

There are more than 1 definitions for echo and reverb. The sound emitted by the source persists for sometime even after the sound emitting source stops emitting sound. this "persistence of audible sound even after the source has stopped emitting sound is called reverberation". whereas, echo is the "reflection of sound after hitting some object". we can differentiate them this way, If this distance is short, such as in a room or theater, the sound will be reflected back to the source in less than one-tenth of a second. This effect is reverberation. When reflected sound travels a greater distance, such as a river valley, and takes more than one-tenth second to return, it is referred to as an echo. similarity is that both are reflections of sound.